Original Research

Assessing the effectiveness of invasive alien plant management in a large fynbos protected area

Tineke Kraaij, Johan A. Baard, Diba R. Rikhotso, Nicholas S. Cole, Brian W. van Wilgen
Bothalia | Vol 47, No 2 | a2105 | DOI: https://doi.org/10.4102/abc.v47i2.2105 | © 2017 Tineke Kraaij, Johan A. Baard, Diba R. Rikhotso, Nicholas S. Cole, Brian W. van Wilgen | This work is licensed under CC Attribution 4.0
Submitted: 31 May 2016 | Published: 31 March 2017

About the author(s)

Tineke Kraaij, School of Natural Resource Management, Nelson Mandela Metropolitan University, South Africa
Johan A. Baard, Scientific Services, South African National Parks, South Africa
Diba R. Rikhotso, Scientific Services, South African National Parks, South Africa
Nicholas S. Cole, Biodiversity Social Projects, South African National Parks, South Africa
Brian W. van Wilgen, Centre for Invasion Biology, Department of Botany and Zoology, University of Stellenbosch, South Africa


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Abstract

Background: Concern has been expressed about the effectiveness of invasive alien plant (IAP) control operations carried out by Working for Water (WfW). South African legislation now also requires reporting on the effectiveness of IAP management interventions.
Objectives: We assessed the effectiveness of IAP management practices in a large fynbos protected area, the Garden Route National Park, South Africa.
Methods: We undertook field surveys of pre-clearing IAP composition and the quality of treatments applied by WfW during 2012–2015 in 103 management units, covering 4280 ha. We furthermore assessed WfW data for evidence of change in IAP cover after successive treatments, and adherence to industry norms.
Results: Despite the development of detailed management plans, implementation was poorly aligned with plans. The quality of many treatments was inadequate, with work done to standard in only 23% of the assessed area. Problems encountered included (1) a complete absence of treatment application despite the payment of contractors (33% of assessed area); (2) treatments not being comprehensive in that select areas (38%), IAP species (11%) or age classes (8%) were untreated; (3) wrong choice of treatment method (9%); and (4) treatments not applied to standard (7%). Accordingly, successive follow-up treatments largely did not reduce the cover of IAPs. Inaccurate (or lack of) infield estimation of IAP cover prior to contract generation resulted in erroneous estimation of effort required and expenditure disparate with WfW norms.
Conclusions: We advocate rigorous, compulsory, infield assessment of IAP cover prior to contract allocation and assessment of the quality of treatments applied prior to contractors’ payment. This should improve the efficiency of control operations and enable tracking of both the state of invasions and effectiveness of management.

Keywords

conservation agencies; effectiveness; implementation; industry norms and standards; interventions; monitoring; project management; weed clearing; Working for Water

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Crossref Citations

1. Contributions to the National Status Report on Biological Invasions in South Africa
John R.U. Wilson, Mirijam Gaertner, David M. Richardson, Brian W. Van Wilgen
Bothalia  vol: 47  issue: 2  year: 2017  
doi: 10.4102/abc.v47i2.2207